Javascript下的日历控件(Calendar)


曾经,我发布过《几个Javascript类》,得到部分朋友的支持;有道是,授之予鱼,不如授之予渔。同时结合朋友们的评价,我对该日历控件做了兼容性检查,已经“基本”支持火狐浏览器应用了;遗留一个小问题,火狐下面“日”提取有问题,不知道有兴趣的朋友能不能在读完本文后自己动手修正该漏洞(提示:火狐不支持 element.innerText,但支持 innerHTML :))。

  每个人都是从“不会”到“会”(或者,从无到有)走过来的。当初为了这样一个在静态 html 文件可应用的轻量级控件,找了不少站点。源于自己出身于 c#,故在应用方式上做了类 c# 包装。

  先谈怎么应用,然后说我是怎么实现的。以下是我在源码包中的演示代码:

function CalendarDemon(){ 
/// <summary> 
/// 如何使用 Calendar 类的演示代码. 参见代码 JsLibrary/Html/Calendar.js. 
/// 请尊重作者劳动, 引用需注明出处. 
/// Howard.Queen@hotmail.com, 2008-07-03. 
/// http://howard-queen.cnblogs.com/ 
/// </summary> 
 
 
  //全局变量 
  window.myCalendar = null;    //日历控件 
  window.currentDay = null;    //当前选择日期 
  window.myTextBox = null;     //当前显示日期的控件 
  window.DayChangedCallback = null;//日历选择日期的回调方法 
  window.MyCalendarPerforms = null;//激活日历的方法, 通过显示控件的相关事件调用 
 
  //日历选择日期的回调方法 
  DayChangedCallback = function(sender, args){ 
    try{ 
      currentDay = args; 
      myTextBox.value = currentDay.GetText("年", "月", "日");//输出所选日期. 自定义日期序列化. 
      //myCalendar.Hidden();//掩藏控件     
    } 
    catch(e){ 
      alert(e.message); 
    } 
  } 
   
  //激活日历的方法 
  MyCalendarPerforms = function(textBox){ 
    try{ 
      if(myCalendar.IsVisible()) 
        myCalendar.Hidden();//掩藏控件 
      else{ 
        if(myTextBox.value != '')//注意: myTextBox == textBox 
          currentDay.FromText(myTextBox.value, "年", "月", "日");//获取已有日期. 注意根据日期的格式, 让系统进行反序列. 
        myCalendar.Show(myTextBox, currentDay);//设置日历显示日期. Show(sender, currentDay), 日历将显示在 sender 附近, 初始化时显示 currentDay. 
      } 
    } 
    catch(e){ 
      alert(e.message); 
    } 
  } 
   
  //日历显示容器 
  document.write("<div id='calendarPannel' style='position:absolute; z-index:1; dispay:none;'></div>"); 
  var pannel = document.getElementById('calendarPannel');  
   
  //日期显示绑定的控件 
  document.write('<input id="myTextBox" type="text" onclick="javascript:MyCalendarPerforms(this);" />'); 
  myTextBox = document.getElementById('myTextBox'); 
   
  //本地化, 缺省为英文 
  var months = new CalendarMonths(["一月", "二月", "三月", "四月", "五月", "六月", "七月", "八月", "九月", "十月", "十一月", "十二月"]); 
  var weekdays = new CalendarWeekDays(["日","一","二","三","四","五","六"]); 
     
  //设置初始日期. 缺省参数则为今天. 
  currentDay = new CalendarDay();//currentDay = new CalendarDay(2008, 5, 12); 
   
  //创建日历控件. 注意自定义日历显示位置的位移差, 此处用了(5, -150). 
  myCalendar = new Calendar('myCalendar', pannel, DayChangedCallback, 5, -150, currentDay, months, weekdays); 
} 

应用它涉及到 5 个关键全局变量的定义。该控件实例,当前所选择的日期实例,显示当前日期的绑定控件,日期选择后的回调函数以及激活日历的方法。月份等显示支持本地化设置,甚至当前日期的输出也支持本地化。

  --------------------------------------------------------------------------------

  “揭密该控件的实现内幕”:

/// <reference path="Tooltip.js"/> 
 
function Calendar(Id, pannel, SelectedDayChangedEvent, toper, lefter, selectedDay, calendarMonths, calendarWeekDays){ 
/// <summary> 
/// 日期选择控件. 月份从 1 开始.使用方法参见示例代码 JsDemons/Html/CalendarDemon.js. 
/// 参考版本《日期选择 - BY ziyue, By Jiang Hongbin等》. 
/// <see cref="http://web-v.com/article.asp?id=3"/> 
/// <seealso cref="http://web-v.com/trackback.asp?tbID=3&action=addtb&tbKey=2fefac8959f18cceb46771512eff082b27e97c09"/> 
/// 请尊重作者劳动, 引用需注明出处. 
/// Howard.Queen@hotmail.com, 2008-07-03. 
/// http://howard-queen.cnblogs.com/ 
/// 2008-07-10  
///   1, 修改 node.innerText 为 node.innerHTML. 完美支持 Firefox. 
///   2, 添加年份无上下限功能. 
///   3, 添加当前所选日期亮显功能. 
///   4, 更改了自定义日期序列化与反序列化, 使得更加友好. 
///   5, 采用显示缓存策略以提高性能. 
///   6, 一些方法的命名更改. 
/// </summary> 
/// <param name="Id" type="string">当前控件名称.</param> 
/// <param name="pannel" type="control">显示容器.</param> 
/// <param name="SelectedDayChangedEvent" type="event">选择日期更改事件.</param> 
/// <param name="selectedDay" type="CalendarDay">所选日期.</param> 
/// <param name="calendarMonths" type="CalendarMonths">月名称.</param> 
/// <param name="calendarWeekDays" type="CalendarWeekDays">周中日名称.</param> 
  this._Init(Id, pannel, SelectedDayChangedEvent, toper, lefter, selectedDay, calendarMonths, calendarWeekDays); 
} 
 
Calendar.prototype = { 
  _Init: function(Id, pannel, SelectedDayChangedEvent, toper, lefter, selectedDay, calendarMonths, calendarWeekDays){ 
  }, 
  _DrawCallback: function(sender, args){ 
  /// <summary>回调显示.</summary> 
  }, 
  _Render: function(temp){ 
  /// <summary>[私有]</summary>  
  }, 
  _RenderYear: function(temp){ 
  /// <summary>[私有]</summary> 
  }, 
  _RenderMonth: function(temp){ 
  /// <summary>[私有]</summary>   
  }, 
  _RenderWeek: function(temp){ 
  /// <summary>[私有]</summary> 
  }, 
  _RenderDay: function(temp){ 
  /// <summary>[私有]</summary> 
  }, 
  _OnCurrentDayChanging: function(dayCell){ 
  }, 
  _Refresh: function(year, month) { 
  /// <summary>[私有]</summary>     
  }, 
   _CreateCalenday: function(year, month) { 
  /// <summary>[私有]</summary> 
  }, 
  _OnYearChanging: function(sender, args){ 
  }, 
  _OnMonthChanging: function(sender, args){  
  }, 
  _OnDayChanging: function(sender, args){ 
  }, 
  IsVisible: function(){ 
  }, 
  Hidden: function(){ 
  }, 
  Show: function(sender, args){ 
  } 
} 
 
function CalendarDay(year, month, day){ 
/// <summary>Calendar中的日期.</summary> 
  this._Init(year, month, day); 
} 
 
CalendarDay.prototype = { 
  _daysCountOfMonths: new Array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31), 
  _Init: function(year, month, day){ 
  }, 
  _GetSubNumber: function(string, head, tail){ 
  }, 
  CheckDate: function(year, month, day){ 
  /// <summary>检查日期合法性.</summary> 
  /// <param name="year" type="int">年份.</summary> 
  /// <param name="month" type="int">月份.</summary> 
  /// <param name="day" type="int">月中日数.</summary> 
  /// <returns>是否合法.</returns> 
  }, 
  GetDayInWeek: function(){ 
  }, 
  IsLeapYear: function(year){ 
  /// <summary>是否闰年</summary> 
  /// <param name="year" type="int">年份.</param> 
  /// <returns>是否闰年.</returns> 
  },   
  GetMonthDays: function(year, month){ 
  /// <summary>获取月的天数</summary> 
  /// <param name="year" type="int">年份.</param> 
  /// <param name="month" type="int">月份.</param> 
  /// <returns>天数.</returns> 
  }, 
  FromText: function(text, yearCaption, monthCaption, dayCaption){ 
  /// <summary>设置选定日期.</summary> 
  /// <param name="text" type="string">日期表达式, 顺序为年、月、日.</summary> 
  }, 
  GetText: function(yearCaption, monthCaption, dayCaption){ 
  /// <summary>获取选定日期.</summary> 
  }, 
  GetLocalMonth: function(calendarMonths){ 
  }, 
  GetLocalWeekDay: function(calendarWeekDays){ 
  } 
} 
 
function CalendarMonths(names){ 
/// <summary>月枚举.</summary> 
/// <param name="names" type="Array">月自定义名称数组.</param> 
} 
 
function CalendarWeekDays(names){ 
/// <summary>周中日枚举.</summary> 
/// <param name="names" type="Array">周中日自定义名称数组.</param> 
} 

如上所示,我将该控件分解为三个类进行实现,Calendar 只负责绘制子控件以及事件收集,CalendarDay 负责对时间进行核准、计算以及输出,剩下两个类似枚举的辅助类。对于 Tooltip,这是我早前包装的,不是为日历控件特制。这些都有别于原始素材(注意类 Calendar 注释中的 see 以及 seealso 部分),感兴趣的朋友可以就可复用性进行对比。

  Calendar 只对外透露三个方法: Show(),Hidden(),IsVisible()。何时显示、何时掩藏,都由应用开发者定制,这给开发人员在不同场合的应用制造了便利。

  在控件核心类 Calendar 的绘制算法上,我将年(_RenderYear())、月(_RenderMonth())、周(_RenderWeek())、日(_RenderDay())独立为方法进行输出,有利于代码的自说明,更方便朋友们的定制与修正。在后期的更新中,我在“年”下拉框上增加了“更多过去”与“更多将来”下拉选项,使得年份也不会拘泥于某个特定时间段,而扩展到了无限。而在显示控件(Show())时,为了防止大量重复计算,只在初次加载控件时进行绘制;但这造成一个小问题,用户当前输入框中的内容只在初始化会同步到控件,其他时刻,控件将忽略。如下代码:

Show: function(sender, args){ 
  /// <summary>显示控件.</summary> 
  /// <param name="sender" type="control">发送者.</param> 
  /// <param name="args" type="CalendarDay">当前日期.</param> 
    if(this._yearsSelect == undefined){//第一次加载. Tooltip 中有对当前控件的缓存, 因此这里没有必要重复计算. 
      this.selectedDay = args; 
      this.offsetTop = sender.offsetTop; 
      this.offsetLeft = sender.offsetLeft; 
      this.clientHeight = sender.clientHeight; 
      this.clientWidth = sender.clientWidth; 
      this._toolTip.Show(sender, this); 
      this._yearsSelect = document.getElementById([this.Id, '_yearsSelect'].join('')); 
      this._monthsSelect = document.getElementById([this.Id, '_monthsSelect'].join('')); 
      this._daysTable = document.getElementById([this.Id, '_daysTable'].join('')); 
      for (var weekIndex = 0, dayInWeek = 0; weekIndex < this._daysTable.rows.length; weekIndex++){ 
        for (; dayInWeek < this._daysTable.rows[weekIndex].cells.length; dayInWeek ++){  
          cell = this._daysTable.rows[weekIndex].cells[dayInWeek];  
          switch(dayInWeek){ 
            case 0://星期日 
              cell.style.color = 'red'; 
              break; 
            case 6://星期六 
              cell.style.color = 'green';  
              break; 
            default://其他 
              break; 
          } 
        } 
        dayInWeek = 0; 
      } 
      this._CreateCalenday(this._yearsSelect.value, this._monthsSelect.value); 
    } 
    else{ 
      this._toolTip.Show(sender, this); 
    } 
  } 

在日期类 CalendarDay 的设计上,针对日期的输出形式仍有较大开发空间。在后期的更新中,我只是简单的加了对年月日的重命名输出,以及对该输出的反向识别,但没有实现类 c# 的 ToString("yyMMdd") 等方法。看我的具体实现:

FromText: function(text, yearCaption, monthCaption, dayCaption){ 
  /// <summary>设置选定日期.</summary> 
  /// <param name="text" type="string">日期表达式, 顺序为年、月、日.</summary> 
    if(text == undefined || text == null || text == ''){ 
      throw {name:"ArgumentNullException", message:"参数为空, 参数名 text."}; 
    } 
    if(yearCaption == undefined || yearCaption == null || yearCaption == '') 
      yearCaption = '-'; 
    if(monthCaption == undefined || monthCaption == null || monthCaption == '') 
      monthCaption = '-'; 
    if(dayCaption == undefined || dayCaption == null) 
      dayCaption = ''; 
    var year = parseInt(this._GetSubNumber(text, '', yearCaption)); 
    var month = parseInt(this._GetSubNumber(text, yearCaption, monthCaption)); 
    var day = parseInt(this._GetSubNumber(text, monthCaption, dayCaption));    
    this.CheckDate(year, month, day); 
    this.year = year; 
    this.month = month; 
    this.day = day; 
    this._dayInWeek = -1; 
  }, 
  GetText: function(yearCaption, monthCaption, dayCaption){ 
  /// <summary>获取选定日期.</summary> 
    if(yearCaption == undefined || yearCaption == null || yearCaption == '') 
      yearCaption = '-'; 
    if(monthCaption == undefined || monthCaption == null || monthCaption == '') 
      monthCaption = '-'; 
    if(dayCaption == undefined || dayCaption == null) 
      dayCaption = ''; 
    return [this.year, yearCaption, this.month, monthCaption, this.day, dayCaption].join(''); 
  },
  --------------------------------------------------------------------------------

  开发过程的乐趣在于,你所做的给自己或者别人带来了一些便利;对于学习开发的入门兄弟来说更是如此。总是说程序员大概都是懒人,能复用的代码,绝不写第二遍;有些人甚至因此偏执于搞复用:用最少的现有代码,延用过去做好的“控件”。但能否在各种场景下复用,就看你对经验的总结了。

  虽然都是小把戏,但还是善意的提醒朋友们:将一个计算过程分滩给多个方法,每个方法短而功能明确,这对以后追加功能或是查找漏洞都会很有帮助。什么时候,我能把设计模式给搞透

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